U.S. sees Russian moves in Donbas as "prelude" to larger offensive

The United States reportedly views Russian forces moving to eastern Ukraine as a "prelude" to a larger offensive in the Donbas region.

Reuters Foreign Policy correspondent Idrees Ali tweeted on Tuesday that a senior U.S. official told him that "78 Russian battalion tactical groups" are in Ukraine, two of which came in the last 24 hours.

Russia's combat power is down about 75% from where it was before the invasion of Ukraine, Ali added.

"Over the last several days, you can continue to see the Russians are doing what we call 'shaping,'" Pentagon spokesman John Kirby told reporters the previous day.

"They're trying to set the conditions for more aggressive, more overt and larger ground maneuvers in the Donbas," he said.

The move comes as some Western military experts believe Russian President Vladimir Putin has strategically lost the war already.